We propose to study functional regeneration in the feeding system of the gastropod mollusc, Aplysia californica. The first specific aim is to ascertain the capacity for recovery of consummatory feeding behavior following bilateral crushes to central nerve tracts that connect the cerebral and buccal ganglia. Behavioral parameters will be measured from direct observations and from videotaped images of subjects taken following the lesion to quantify the recovery of biting, swallowing, and rejection. The second specific aim is to determine if regeneration of connections, by identified neurons involved in consummatory feeding, accompanies behavioral recovery, and to test if these connections are normal. For this specific aim we will use simultaneous multiple intracellular and extracellular recordings and stimulation. the third specific aim is to test for changes in cellular properties in response to CNS injury and during functional regeneration using immunocytochemistry, electrophysiological recordings, and electron microscopy. The proposed studies will provide answers to fundamental questions about neuronal repair and functional regeneration in vivo. It is likely that some cellular mechanisms of neuronal repair evolved in ancestors common to molluscs and mammals; if so, our results will be applicable to higher vertebrate organisms, including humans, where regeneration in the CNS is more limited. An important aspect of this proposal is the combination of cellular and behavioral studies. With this integrated approach, we can begin to describe the contribution by sensory, pattern initiator (i.e., command), and modulatory neural systems to behavioral recovery in terms of functional regeneration of specific neuronal connections.